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Finding the Fourth Proportional to 696.80, 1,045.20 and 285.80

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Solution

The fourth proportional to 696.80, 1,045.20 and 285.80 is: 428.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    696.80 : 1,045.20 = 285.80 : x
  2. Step 2: Convert to fraction form
    696.80/1,045.20 = 285.80/x
  3. Step 3: Cross multiply
    696.80x = 1,045.20 × 285.80
  4. Step 4: Simplify right side
    696.80x = 298,718.16
  5. Step 5: Solve for x
    x = 298,718.16/696.80
  6. Step 6: Final answer
    x = 428.70

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.